Local variance of atmospheric 14C concentrations around Fukushima Dai-ichi Nuclear Power Plant from 2010 to 2012

摘要

Radiocarbon (¹⁴C) has been measured in single tree ring samples collected from the southwest of the Fukushima Dai-ichi Nuclear Power Plant. Our data indicate south-westwards dispersion of radiocarbon and the highest ¹⁴C activity observed so far in the local environment during the 2011 accident. The abnormally high ¹⁴C activity in the late wood of 2011 ring may imply an unknown source of radiocarbon nearby after the accident. The influence of ¹⁴C shrank from 30 km during normal reactor operation to 14 km for the accident in the northwest of FDNPP, but remains unclear in the southwest.